Keywords = Frame of subspaces
Number of Articles: 1
Ultra Bessel sequences in direct sums of Hilbert spaces
Volume 2, Issue 1, September 2015, Pages 55-64
M. R. Abdollahpour, A. Rahimi
Abstract In this paper, we establish some new results in ultra Bessel sequences and ultra Bessel sequences of subspaces. Also, we investigate ultra Bessel sequences in direct sums of Hilbert spaces. Specially, we show that {( fi, gi)}∞ i=1 is a an ultra Bessel sequence for Hilbert space H ⊕ K if and only if { fi}∞ i=1 and {gi}∞ i=1 are ultra Bessel sequences for Hilbert spaces H and K, respectively.